By Jon Herskovitz
AUSTIN, Texas, Jan 29 (Reuters) - Texas plans on Thursday to execute Robert Ladd, 57, who was convicted of beating a woman to death with a hammer in her home in 1996 and then setting her body on fire.
The execution by lethal injection is scheduled for 6 p.m. CST at the state's death chamber in Huntsville.
If it goes ahead, Ladd would be the 520th person executed in Texas since the U.S. Supreme Court reinstated the death penalty in 1976, the most of any state. Nearly 40 percent of all the executions in the United States in that time have taken place in Texas.
Lawyers for Ladd have petitioned the U.S. Supreme Court to halt the execution, saying he is intellectually disabled with an IQ of 67 and that executing him would be unconstitutional.
Ladd was convicted of sexually assaulting Vicki Garner, beating and choking her to death, and then setting her body on fire. She was found half naked with her legs and wrists bound by electric cords, state officials said.
Ladd stole several items from the residence and exchanged them for cocaine, the State Attorney General's Office said.
DNA evidence and a palm print found at the scene implicated Ladd in the crime, it said.
Ladd won a last-minute appeal of an execution planned for April 2003 to give the courts more time to examine records indicating he was mentally impaired.
Courts allowed the execution to be put on hold until 2013 when his petition for a stay was struck down by a U.S. district court.
(Reporting by Jon Herskovitz; Editing by Peter Cooney)